Turn on thread page Beta
    • Thread Starter
    Offline

    2
    ReputationRep:
    I don't understand the answer to this, or how to even get there. I expanded/simplified it first, but still get the wrong answer. help. pls.

    f(x) = (2x^3/2 - 3x^-3/2)^2 +5
    f(x) = 5

    Find the value of x to 3 sf
    Offline

    12
    ReputationRep:
    What was the original question?
    • Very Important Poster
    Offline

    21
    ReputationRep:
    Very Important Poster
    (Original post by indignation)
    I don't understand the answer to this, or how to even get there. I expanded/simplified it first, but still get the wrong answer. help. pls.

    f(x) = (2x^3/2 - 3x^-3/2)^2 +5
    f(x) = 5

    Find the value of x to 3 sf
    Would you mind posting the full question?

    Edit: It looks like you've posted everything, sorry. See below.
    Offline

    1
    ReputationRep:
    (Original post by indignation)
    f(x) = (2x^3/2 - 3x^-3/2)^2 +5
    f(x) = 5

    Find the value of x
    It looks like it wants you to put

    (2x^3/2 - 3x^-3/2)^2 +5 = 5

    But without the full question its hard to tell (as others have said)
    Offline

    21
    ReputationRep:
    (Original post by indignation)
    I don't understand the answer to this, or how to even get there. I expanded/simplified it first, but still get the wrong answer. help. pls.

    f(x) = (2x^3/2 - 3x^-3/2)^2 +5
    f(x) = 5

    Find the value of x to 3 sf
    No need to expand
    if f(x) = 5 then (2x^3/2 - 3x^-3/2)^2 = 0
    Solving for x from there should be straightforward

    Posted from TSR Mobile
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Quantum Confinement)
    It looks like it wants you to put

    (2x^3/2 - 3x^-3/2)^2 +5 = 5

    But without the full question its hard to tell (as others have said)
    yes that is right, but how do you correctly simplify the (2x^3/2 - 3x^-3/2)^2?
    • PS Helper
    • Study Helper
    Offline

    13
    ReputationRep:
    PS Helper
    Study Helper
    (Original post by indignation)
    yes that is right, but how do you correctly simplify the (2x^3/2 - 3x^-3/2)^2?
    g(x)^2 = 0 if and only if g(x) = 0.
    • Thread Starter
    Offline

    2
    ReputationRep:
    ohhh, that makes a lot of sense
    (Original post by Smaug123)
    g(x)^2 = 0 if and only if g(x) = 0.
    Offline

    1
    ReputationRep:
    (Original post by indignation)
    yes that is right, but how do you correctly simplify the (2x^3/2 - 3x^-3/2)^2?
    Square root both sides then take it from there
 
 
 

3,314

students online now

800,000+

Exam discussions

Find your exam discussion here

Poll
Should universities take a stronger line on drugs?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.